The instant invention relates to a resealable, flexible plastic envelope having superior durability to those of the prior art. In particular, the closure flap of the instant invention can be repeatedly opened and resealed without damaging the integrity of the envelope.
Adhesive type closure arrangements have been used to seal and/or close plastic bags such as those used for sandwiches, garbage containers, and other household uses. For example, U.S. Pat. No. 4,519,095 to Clayton describes a resealable flexible thermoplastic bag wherein the closure comprises at least one female channel member or strip-affixed to the bag and having a pressure sensitive adhesive layer on an internal portion of the channel strip such that the thickness of the adhesive layer is less than the interior depth of the walls of the channel strip. During shipment and storage the walls of the channel hold the pressure sensitive adhesive layer away from adjacent surfaces to prevent inadvertent sticking. Sealing of the bag is achieved by contacting the channel strip with a surface of the bag and exerting pressure along the strip whereby the pressure sensitive adhesive is contacted with a substantially flat portion of the surface and adhered thereto.
Clayton discloses a resealable plastic bag containing a channel with the adhesive layer positioned on a flap of the bag, a channel with the adhesive positioned on the body of the bag over which the flap will fold, and two female channel strips positioned on opposite sides of a bag opening to affect a double seal by pressing the two channels into contact such that one wall or bead of each channel is contacted by the adhesive layer in the opposing channel.
Other patents disclosing resealable, flexible plastic bags include U.S. Pat. Nos. 5,791,783 and 5,783,012, both to Porchia et al.; U.S. Pat. No. 5,527,112 to Dais et al.; and U.S. Pat. No. 6,032,854 to Greer et al.
One possible use of the resealable, flexible plastic bag is as a packing list envelope which is commonly used by courier services such as FedEx, U.S. Postal Service, etc. When a package is sent through the courier service, a list of the contents of the package, addresses of the addressee and sender, and various other pertinent information are placed into a transparent packaging envelope with the addresses visible through the front of the envelope. The back of the envelope is then attached to the package with an adhesive. Because, during the package processing, the envelope is subject to being opened and resealed for placing or removing items in the envelope, it is desirable to have an envelope that can repeatedly be opened and resealed without losing its integrity.
Thus it is desirable to avoid the problems of the prior art envelopes and provide a packing slip envelope that is resealable without damaging the integrity of the envelope and without the high cost.
One aspect of the invention is related to a packing slip envelope that is resealable with an resealable adhesive without damaging the integrity of the envelope. If the packing slip envelope to be attached to a package, an adhesive preferably permanent is provided on the back of the envelope. The envelope comprises a front sheet, a back sheet, and a closure flap. The front sheet has the same width as the back sheet and a shorter height. The back and front sheet are attached at their respective side edges and bottom edges via heat sealing. The closure flap attaches to the back sheet at their respective top edges via a permanent adhesive and overlaps the front sheet. To seal the envelope, a resealable adhesive is placed on the outside and adjacent to the top edge of the front sheet. The adhesive binds the closure flap overlap to the front sheet to seal the envelope. The permanent adhesive used to join the closure flap to the back sheet allows the envelope to be opened and resealed without damaging the several joints at the edges of the envelope. The envelope is preferably made of a plastic and can be either transparent or translucent. Printing can be provided on the face sheet or backing sheet.
Another aspect of the invention is related to the method of making the packing slip envelope.